I needed a challenge and think this radio is winning. I have had this sitting for about 8 years and figured I would try it. I have no history on it. It had a bad audio amp TDA1905 Bad Final and driver. R157 cooked and a few of the caps that usually go when the final goes. I see no modifications in this radio so I do not know how how all those parts went bad. The radio is now transmitting.
The problem I have no receive and full S meter when plugged in. I forgot to mention this was half stuck in transmit and replacing a bad transistor Q136 partially solved that problem.
So voltages on IC104 check good I would guess. voltages are a bit high but same ratio on RX and TX.
Q134, 124, 125, 127, all good. D147 and D24 and D25 good and 2 diodes on swr board D151 and D152 good.
I also just in case tried a different CPU board and same thing so I assume no problems there.
So whatever shorted out all those parts possibly reverse polarity plug in or lightning shorted another part but I am not sure where else to look. Any suggestions are appreciated.
Thanks.
The problem I have no receive and full S meter when plugged in. I forgot to mention this was half stuck in transmit and replacing a bad transistor Q136 partially solved that problem.
So voltages on IC104 check good I would guess. voltages are a bit high but same ratio on RX and TX.
Q134, 124, 125, 127, all good. D147 and D24 and D25 good and 2 diodes on swr board D151 and D152 good.
I also just in case tried a different CPU board and same thing so I assume no problems there.
So whatever shorted out all those parts possibly reverse polarity plug in or lightning shorted another part but I am not sure where else to look. Any suggestions are appreciated.
Thanks.